Agricultural seeding implements are configured to open a furrow in the soil and to deposit an agricultural product such as seed or fertilizer in the furrow. Most often, and particularly where the product in the furrow is seed, it is desired that a large proportion of the soil moved to form the furrow drop back into the furrow to cover the product.
A typical seeding implement comprises a frame mounted for movement along the ground, and a plurality of shanks attached at top ends to the frame and extending downward, with a furrow opener attached to the bottom end. Typically the shanks will be pivotally attached to the frame by a trip mechanism that allows the shanks to move rearward to clear obstructions in the field, such as rocks, roots, and the like.
Hoe-type furrow openers typically comprise a rigid member such as a hoe, knife, shovel or the like attached to the bottom of the shank. Disc furrow openers are also well known where a disc is rotatably mounted to the bottom of the shank at an angle such that the rotating disc cuts a furrow.
Where the speed of operation is relatively slow, up to about 4 miles per hour (mph), the soil moved aside by most furrow openers to form the furrow will largely fall back into the furrow, covering the product. As the operating speed increases, a larger proportion of the soil moved by the furrow openers is thrown away from the furrow and falls on the field surface adjacent to the furrow. At desired operating speeds of 5-7 mph, it is difficult to keep a satisfactory soil cover over the furrow.
U.S. Pat. No. 5,782,307 to Forsyth discloses a furrow closing apparatus comprising a pair of discs mounted to the shank such that one disc rolls along the ground on each side of the furrow opener. Soil thrown to the side by the furrow opener strikes the discs and falls back to the ground adjacent to the furrow and to some extent at least on the furrow. The discs are also oriented at an angle to move soil adjacent to the furrow toward the furrow and so cover the furrow.
The paired disc configuration of Forsyth is also utilized in U.S. Pat. No. 5,595,249 to Steinberger where a pair of discs is mounted to a shank to level the ground behind an implement, and also in U.S. Pat. No. 4,485,878 to Uken in a row crop cultivator where a pair of discs is mounted to a shank to prevent soil thrown by the shank at higher speeds from covering and damaging young plants.
A similar arrangement is manufactured by Atomjet Industries of Brandon, Manitoba, Canada for closing a furrow. A bracket is mounted on a midpoint of the shank and an arm is pivotally mounted to the bracket on each side of the shank and extends downward and rearward to a disc rotatably mounted on the end of each. The arm and disc float with no downward pressure on the arm. The angle of the discs to the direction of travel can be varied to change the orientation of the discs to change the amount and direction of movement of the soil or crop residue engaged by the discs.